[英]React Native - How to get same output in two different pages in react-native with same code?
[英]How to use same data in two different .js file (React Native)
在下面的js文件中,我們創建一個整數(ttSelectedItem)。 如何在另一個.js文件中使用它? (無需單擊任何按鈕)AsyncStorage是否可以解決該問題? 如果屬實,怎么辦?
import React, { Component } from 'react'; import {Platform,StyleSheet,Text,View,Image,ImageBackground} from 'react-native'; import Picker from 'react-native-wheel-picker' var PickerItem = Picker.Item; var numberList = []; var ttSelectedItem, for (let i = 0; i < 41; i++){ numberList.push(i.toString()); } export default class yks extends Component<{}> { constructor(props) { super(props); this.state = { ttSelectedItem : 20, itemList: numberList, }; } onPickerSelect (index, selectedItem) { this.setState({ [selectedItem] : index, }) } render () { return ( <View> <Picker style={{width: "100%", height: "100%"}} selectedValue={this.state.ttSelectedItem} onValueChange={(index) => this.onPickerSelect(index, 'ttSelectedItem')}> {this.state.itemList.map((value, i) => ( <PickerItem label={value} value={i} key={"money"+value}/> ))} </Picker> </View> ); } }
您可以創建一個文件ttSelectedItem.js
並將其導入所需的所有組件中。
例:
//ttSelectedItem.js
const ttSelectedItem = 'Hello';
export default ttSelectedItem
//YourComponent.js
import ttSelectedItem from './path-to-ttSelectedItem';
class YourComponent extends React.Component {
console.log(ttSelectedItem); // print Hello
}
更多信息: https : //developer.mozilla.org/zh-CN/docs/web/javascript/reference/statements/export
您還可以將prop從父級組件傳遞到其子級。
例:
// App.js
import FirstComponent from 'path-to-first-component';
import SecondComponent from 'path-to-second-component';
class App extends React.Component {
render() {
return (
<View>
<FirstComponent ttSelectedItem={'Hello'} />
<SecondComponent ttSelectedItem={'Hello'} />
</View>
)
}
}
// FirstComponent.js
class FirstComponent extends React.Component {
console.log(this.props.ttSelectedItem) //print Hello
}
export default FirstComponent
// SecondComponent.js
const SecondComponent = (props) => {
console.log(props.ttSelectedItem) //print Hello
}
export default SecondComponent
根據代碼的復雜程度,您可以使用HOC連接一些數據並傳遞組件
例:
//ttSelectedItem.js
const ttSelectedItem = (Component) => {
return <Component ttSelectedItem={'Hello'} />
}
export default ttSelectedItem;
//YourComponent.js
import ttSelectedItem from 'path-to-ttSelectedItem';
class YourComponent extends Component{
(...)
console.log(this.props.ttSelectedItem); //print Hello
(...)
}
export default ttSelectedItem(YourComponent);
更多詳細信息: https : //reactjs.org/docs/higher-order-components.html
或者,如果您需要更復雜的代碼,則可以使用Redux Store保留此數據
使用Redux和ReduxThunk的示例:
//App.js
import ReduxThunk from 'redux-thunk';
import { Provider } from 'react-redux';
import { createStore, applyMiddleware } from 'redux';
import reducer from 'path-to-your-reducer';
import YourComponent from 'path-to-your-component';
class App extends Component {
render() {
const store = createStore(reducer, {}, applyMiddleware(ReduxThunk));
return (
<Provider store={store}>
<YourComponent />
</Provider>
);
}
}
// YourComponent.js
import { connect } from 'react-redux';
class YourComponent extends React.Component {
console.log(this.props.ttSelectedItem) // prints Hello
}
const mapStateToProps = function(state){
return {
ttSelectedItem: state.ttSelectedItem,
}
}
export default connect(mapStateToProps, {})(MainAppContainer)
// Reducer.js
const INITIAL_STATE = {
ttSelectedItem: 'Hello',
};
export default (state = INITIAL_STATE) => {
return state;
};
更多信息: https : //redux.js.org/basics/store
最后一個示例只是為了展示使用Redux處理組件之間的數據的另一種方法。 僅在處理真正復雜的數據共享時才應使用它。
我建議您僅遵循第一個示例,這可能就足夠了
希望能幫助到你
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